Compost, Cows and Carbon Markets
John Wick and the Marin Carbon Project
When John Wick purchased a beautiful piece of rolling rangelands in Marin County’s Nicasio Valley in 1998, he thought getting rid of the cows might be the best thing to do for the land. A year later, invasive weeds began to choke the ungrazed land and attempts at weed removal, first by labor-intensive hand pulling and then with chemicals, failed. Wick turned to local rangeland management expert Dr. Jeffrey Creque and together they hatched a sustainable grazing management plan that helped bring back a healthy plant community to the land. They also upped the ante by challenging themselves to manage the land in a way that would actually benefit the climate, and in the process they planted the seeds of the Marin Carbon Project.
Created by a coalition of key local organizations focused on agricultural sustainability, the Marin Carbon Project addresses how farmers and ranchers can implement tangible climate solutions on the ground. The project includes local land trusts, government agencies that work with local producers, universities and nonprofit organizations all working together to determine how to best manage rangelands to increase carbon in the soil.
Rangeland Management for Carbon
California’s golden hills and green meadows represent over 50 percent of the land area in the state and have the potential to take the excessive loads of carbon from the atmosphere into the soil, effectively becoming large carbon reservoirs. In their search for water and nutrients, grasses in these typically semi-arid landscapes allocate a lot of the carbon they pull from the atmosphere to their root systems. It is through these same roots that carbon can be moved to long-term storage in the soil. Many ranchers and rangeland managers already operate with the knowledge that taking care of the soil’s health is a smart investment, but the notion that they could rapidly increase the carbon stored in rangeland soil by utilizing a time-tested farming and gardening tradition — compost — is unusual.
San Francisco knows a lot about the benefits of compost. The city has a thriving curbside compost program, which diverts food and yard waste away from landfills, where it would produce methane as it decomposes. This diversion is critical to the equation because methane is a potent global warming force, 28 to 34 times more potent than carbon dioxide. The composting process transforms waste into a great soil amendment that is sold to Bay Area farmers. Soils amended with compost hold more water, are more fertile and are less prone to erosion.
As the Marin Carbon Project’s agricultural experts brainstormed for climate-beneficial practices, the idea of adding compost to rangelands as an alternative to the historical management practice of manure application was seen as an innovative win-win that would reduce organic waste while building the health of the soil. UC Berkeley biogeochemist Dr. Whendee Silver and her team were recruited to measure and analyze the effects.
UC Berkeley scientists found that a single application of a half-inch of compost (delivered by the truckload) on rangeland increased long-term carbon storage in the soil for multiple years in a row.
Measuring Climate Benefits
Dr. Silver and her team were initially skeptical that there would be any measureable benefits to adding compost to rangelands, but were curious enough to pursue the idea. They added a single application of a half-inch of compost over tennis court–sized plots at both John Wick’s ranch and at the UC Research and Education Center in the Sierra Foothills. Doctoral student Becca Ryals conducted four years of intensive data collection and the results surprised the initially skeptical Dr. Silver. The one-time application of compost increased the amount of grass for the cows to eat (forage production) by 40–70 percent per year and increased the carbon stored in the soil by one metric ton per hectare per year. To put this in context, a one-time application of compost on just a quarter of California’s rangelands (6 million hectares) would offset half of the state’s commercial and residential emissions every year.
But what about the overall greenhouse gas emissions of this practice? And the emissions created from trucking compost to the fields? Dr. Marcia DeLonge determined an overall lifecycle GHG emission reduction benefit of over 30 tons per hectare, if avoided methane emissions from diversion of organics from landfills is included in the analysis.
Great results — but how does this translate into actual practice on ranches in California and beyond?
Implementation and Carbon Markets
In order to encourage wide adoption, the Marin Carbon Project must now illustrate that the practice of compost application on rangelands is both cost effective and can work beyond the first prototypes.
Making the economic case for implementation of this practice has just begun. Compost is expensive and the savings that come from the increased feed for cows alone may be reason enough for some ranchers to implement this practice. Increases in water holding capacity are an incentive for others. But by measuring and quantifying the carbon benefits of compost application, the Marin Carbon Project has opened the door to a new economic driver: paying ranchers for not just their beef, but for doing something good for the environment, too. There is a ready market: California has created one of the first regulatory carbon markets in the country, requiring polluting industries to reduce their emissions or buy emission reductions in the form of carbon offsets from others who have reduced emissions, like ranchers who are applying compost to the land. Today, the rules to create and sell offsets are rather rigorous — making it an expensive market for ranchers to get into. Even so, the potential of harnessing private investment dollars through California’s carbon market to combat climate change is an exciting one — especially as government and philanthropic dollars dwindle.
Urban areas in the Bay Area generate tons of food and yard waste annually, while nearby rural areas have hundreds of thousands of acres of rangeland. As the Marin Carbon Project has shown, linking them by turning urban greenwaste into a rangeland soil amendment has clear ecological benefits. But the cost to ranchers of purchasing and applying the compost is holding back its widespread adoption. To address this, the project is working to integrate rangeland stewardship into California’s carbon market, so ranchers could earn money for sequestering carbon in their soil. The financial numbers don’t pencil out just yet, but that could change in the coming years. If it does, the Marin Carbon Project will have found a way to improve the economic viability of ranching and reduce the region’s ecological footprint by utilizing compost, cows and carbon markets.